<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
  </head>
  <style>
    body > div {
      position: absolute;
    }
    .one {
      top: 10px;
      left: 10px;
      width: 200px;
      height: 200px;
      background-color: red;
    }
    .two {
      z-index: 1;
      top: 40px;
      left: 40px;
      width: 300px;
      height: 300px;
      background-color: green;
    }
    .three {
      z-index: 0;
      top: 70px;
      left: 70px;
      width: 400px;
      height: 400px;
      background-color: blue;
    }
  </style>
  <body>
    <div class="one"></div>
    <div class="two"></div>
    <div class="three"></div>
  </body>
</html>
